In the past, there have been many forms of safety or pressure relief valves for effectively dissipating and exhausting excessive compressed air in a storage reservoir, or the like, to the atmosphere. Generally, these previous spring-load valves include a metallic poppet valve which coacted with a metallic seat to quickly open the valve when a preselected pressure is attained and to sharply close the valve when a definite amount of blow-down has occurred. Normally, these metallic safety valves initially require intricate and expensive machining, and subsequently require extensive and costly lapping operation to attempt to match the mating surfaces of the valve and the valve seat. It has been found that even after all this time-consuming and precision operation to attain the required close tolerances, the metallic safety valves are still prone to leaking either during initial testing or subsequently in service. While there have been numerous attempts to reduce manufacturing time and overall costs of producing metallic type of safety valves, these previous endeavors were also possessed of a number of shortcomings, such as requiring expensive and special designed gaskets or annular sealing rings. Further, the previous attempts to use O-rings as sealing elements failed either because of being blown out from the valve member or because of chafing and excessive wearing during the opening and closing of the valve member with the valve seat.